ABSTRACT
The patient was a 56-year-old male with an 8-year history of Behcet's syndrome, who presented with chest pain. A saccular aneurysm (4×4cm) of the descending aorta was disclosed by X-ray and CT. Impending rupture of the aneurysm was suspected and emergency surgery was performed under cardiopulmonary bypass. The aneurysm consisted of a large thrombus, and a punched-out lesion on the aorta (φ10mm) was found beneath the thrombus. Closure with a Dacron patch was carried out successfully. Pathologic examination revealed the patient to have vasculo-Behcet's syndrome. Generally this desease has a poor prognosis, especially if an aneurysm is present, since sudden rupture can occur. Thus, prompt surgical treatment of the aneurysm should be considered. The patient was free of recurrence at the time of writing this report.